On 22 July, 4,105 people across Japan were taken to hospital by ambulance for heatstroke. It is the highest single-day national figure the Fire and Disaster Management Agency has recorded since it began the survey in 2008, beating 3,809 on 18 July 2018 by 296 people. The runner-up in the whole series is the following day in 2018, 19 July, at 3,794 — so the new figure clears the old record by more than the old record cleared its own nearest rival.
Two components of the same day are also all-time highs. Transports of people aged 65 or over reached 2,249, against a previous daily maximum of 1,914 on 2 August 2019. Cases classed 重症, severe, meaning an expected inpatient stay of three weeks or more, reached 199 against 182 on that same 2019 day. Deaths on 22 July were nine, which is not a record; the highest daily figure in the series is 19, on 24 July 2010.
The agency publishes only a weekly bulletin and does not rank days. Its 20–26 July edition names 22 July as the peak of a week that carried 18,591 transports nationally, and stops there. The comparison against 2018 comes from the agency’s own archived microdata, which reconciles to the printed annual totals for every year of the series.
The record landed in a season that has, on the headline figure, been lighter than last year. The FDMA’s cumulative for 1 May to 2 August 2026 is 52,201 people against 61,928 for the identical window in 2025 — 15.7 per cent fewer. That comparison mixes two kinds of number, since the 2026 total is part confirmed and part preliminary, and preliminary figures in this series revise upward by around two per cent as cases are settled. Which means 4,105 is a floor.
Split the season at the end of June and the gap disappears. From 1 May to 28 June, 2026 recorded 7,623 transports against 17,278 in 2025 — 55.9 per cent fewer. From 29 June to 2 August, 2026 recorded 44,578 against 44,650 — a difference of 72 people, or one part in six hundred. The whole of the season’s apparent mildness is a cool May and June. Since the end of June, this summer has been running level with 2025, which the agency’s annual report records as the heaviest since the survey began, at 100,510 transports across May to September.
Ranked against the eleven years in which the survey covered the full May-to-August window, 2026 is the fourth heaviest to 2 August, behind 2018 at 66,424, 2025 at 61,928 and 2024 at 56,450, and ahead of 2023 and 2022. It is not a mild summer. It is a summer that started slowly and then concentrated.
That concentration is itself the unusual feature. The 22 July peak accounts for 7.9 per cent of everything the season has recorded so far, against 5.7 per cent for the 2018 record day in its own season and 3.5 per cent for last year’s peak. Set against the surrounding week, 22 July carried 21.7 per cent of a seven-day total, where the 2018 record carried 15.6 per cent.
The composition has shifted too. People aged 65 and over were 54.8 per cent of the record day, against 46.4 per cent of the 2018 record. Transports from educational settings, which were 8.9 per cent of the day in 2018, were 1.8 per cent this time — 73 people out of 4,105. Nearly two in five of those taken to hospital on 22 July, 1,559 of them, were picked up from a residence.
One caveat belongs with the record. The survey’s month coverage is not constant across its eighteen years: 2008 and 2009 cover July to September only, and May is missing from 2010 to 2014 and from 2020. The highest daily figure ever recorded in a month the survey did not always cover is 2,600, on 30 June 2022, well below the 2018 mark, so the record itself is unaffected — but the series is not a clean eighteen-year run of identical windows.